Screw propeller



(No Model.)

` G. ROOKB.

SGRLEW PROPELLER.

No. 484,898. Patented Deo. 8, 18918.

mvewbofc A wzyellwiw. Iva/dw 18 @litem-legi UNITED STATES PATENT OFFICE.

GEORGE ROOKIE, OF EMPORIA, KANSAS.

SCREW PROPELLER.

SPECIFICATION forming part of Letters Patent No. 464,898, dated December 8, 1891. Application filed October 15,1891. Serial No. 408,768. (No model.)

To all whom it may concern:

Be it known that nI, GEORGE ROOKE, of Emporia, in the county of Lyon and State of Kansas, have invented certain new and useful Improvements in Screw Propellers, of which the following is a specification, reference being had to the accompanying drawings.

The object of my invention is to improve the mechanism for propelling the ship from the bow, so that increased speed may be secured beyond what can be obtained by driving a boat from the stern.

My invention relates to boats wherein the bow is formed in two separate parts, one normally above and the other below the waterline. I provide a revolving conical beak (or extension of that part of the bow which is under water) having blades that tend to draw the ship through the water and having peculiar spiral projections back of the blades that diminish the pressure of water upon the bow, and thus tend to increase the speed of the ship.

`My present invention relates particularly to such devices combined with a hollow cylindrical shell which may be applied around the propeller-blades, so as to be either fixed or to rotate with them and to inclose them, substantially as illustrated in the drawings, in which- Figure l is a side elevation of so much of 'the forward part of the hull of a boat as is necessary to illustrate my invention, the shell being shown in section. Fig. 2 is a section on the line 2 2 of Fig. l. Fig. 3 is a section on the line 3 3 of Fig. l. Fig. 4 is a cross-section of the shell, illustrating it as iixed to the boat.

Referring to the letters on the drawings, A indicates the hull of a boat, which is provided at its bow with a separate deck part A and between the keel and the watereline with a conically-tapered part B, which may be `built into the boat or may be provided in one already built by removing a part of the hull and rebuilding that portion' of it. Any kind of boat, whether old ornew, may thus be adapted to use my improvements.

C indicates a conical beak whose base is of the same diameter as the part B, where the beak joins it, and whose sides form a continuation of the taper of that part. Itis mounted by means of the shaft D on suitable bearings E in the interior of the vessel and in the forward part of the .keel F, respectively, and is adapted to be rapidly revolved by any suitable mechanism. (Not sh own in the drawings.) Upon the forward end of the beak are provided blades G, so arranged thereon as to tend to draw the boat through the water when the beak is revolved. Near the largest part of the beak and behind the blades on the beak are provided spirals H, that preferably consist of ribs arranged obliquely and parallel to each other. They should be constructed substantially as shown, so as to throw the water away from the bow of the boat, thereby diminishing the resistance against its onward mo vement and at the same time so as to cause in themselves the minimum resistance to rotation and to forward motion. The form illustrated in the drawings I regard as preferable for the spirals; but it may be varied. lln this form, as shown in the section,Fig. 2,the beak being rotated in the direction of the arrow, the incline K will tend to throw the water away from the submerged part B of the bow and, as it were, open a cavity for the .passage of the bow. The front ends of the spiral ribs are tapered at L, so as to wedge their way into the water as the boat advances and also tend, like the inclined sides K, to throw t-he water away from the submerged part of the bow.

The devices thus far described have been embodied by me in another application for patent; and in the present case I combine with the parts described a hollow cylindrical casing M, iuclosing the propeller-blades, the object of which is to guard and protect them while it admits water freely. The opening into the cylinder from the small end of the beak is greater than that at the opposite end, so that ample water is received as the boat advances for the action of the blades of the screw, and by confining the water around the rear of the blades the shell aids the action of the propeller upon the water and tends to increase its pulling force upon the ship, and also forms a shield. This shell may be either fixed or made to revolve with the screw in practice with the same effect. It can be made IOO of steel or other strong metal and quite thin, of, each spiral having the incline K upon one so thatits resistance to the advance of lche ship side and Ebel-'ront incline L and means for rois buf/slight, and it more than compensates tating the beak, andahollow cylindrical shell for its Weight and resistance' by the service it M, surrounding the propeller-blades, substanf 5 5 performs in connection with the propellerl tially as set forth.

blades. In the drawngsit is shown as adapt- In testimony of all which I have hereunto ed to rotate with the screw-propeller. subscribed my name. v

What I claim s 4 GEORGE' ROOKE. In a boat, the combination of a revoluble "Witnesses: 1 o conical beak C, provided with prop eller-blades L. A. NEWTON,

atits forward end and spiralsI-Iin rear there- J C. SCHMIDT. 

